Ozone hole recovery may reshape southern hemisphere clim...( A full recovery of the stratospheric...)

A full recovery of the stratospheric ozone hole could modify climate change in the Southern Hemisphere and even amplify Antarctic warming, according to scientists from the University of Colorado at Boulder, the National Oceanic and Atmospheric Administration and NASA.

While Earth's average surface temperatures have been increasing, the interior of Antarctica has exhibited a unique cooling trend during the austral summer and fall caused by ozone depletion, said Judith Perlwitz of the Cooperative Institute for Research in Environmental Sciences, a joint institute of CU-Boulder and NOAA. "If the successful control of ozone-depleting substances allows for a full recovery of the ozone hole over Antarctica, we may finally see the interior of Antarctica begin to warm with the rest of the world," Perlwitz said.

Perlwitz is lead author of a new study on the subject to be published April 26 in Geophysical Research Letters. Co-authors include Steven Pawson and Eric Nielson of NASA's Goddard Space Flight Center in Greenbelt, Md., and Ryan Fogt and William Neff of NOAA's Earth System Research Laboratory in Boulder. The study was supported by NASA's Modeling and Analysis Program.

The authors used a NASA supercomputer model that included interactions between the climate and stratospheric ozone chemistry to examine how changes in the ozone hole influence climate and weather near Earth's surface, said Perlwitz.

The study authors calculated that when stratospheric ozone levels return to near pre-1969 levels by the end of the 21st century, large-scale atmospheric circulation patterns now shielding the Antarctic interior from warmer air masses to the north will begin to break down during the austral summer. The circulation patterns are collectively known as a positive phase of the Southern Annular Mode, or SAM.

The scientists found that as ozone levels recover, the lower stratosphere over the polar region will absorb more harmful
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